The present invention relates to gear reduction assembly and in particular to a mounting structure for a rotatable shaft on which a gear is fixed.
In gear reduction mechanisms according to the prior art, two bearings are generally used to support a rotatable shaft on which a gear is fixed. One of the two bearings is usually pressed into a retaining hole in a supporting base and another is usually pressed into a retaining hole in the housing. The supporting base is secured on the housing by screws, so that the rotatable shaft is positioned and mounted correctly relative to the housing.
The position and assembling angle of the rotatable shaft relative to the housing is determined according to the relationship of three positions. The first position is that of a retaining hole in the housing; the second position is that of a retaining hole in the base and the third position is the assembly position of the holding base relative to the housing. The machining precision of the first hole and the second hole, that is, the position precision of the first position and the second position, the machining precision of the screw hole of the supporting base and the machining precision of the screw hole of the housing are not precise enough so that eccentricity of the rotatable shaft of the mechanism and non-uniformity of rotation load and backlash will occur. It is clear that problems such as machining precision are present and the procedure of assembly creates more problems. It is an object of the present invention to improve the problems existing in the prior art.